1. Field of the Invention
The present invention relates to an apparatus and method for treating wastewater and, more particularly, to a method for effectively treating wastewater of high concentration by sequentially performing an aerobic treatment and an anaerobic treatment, and an apparatus therefor.
2. Description of Related Art
In general, while high concentration wastewater can be completely treated by an aerobic treatment, an anaerobic digestion process has been further used to increase the utility of methane gas.
However, the efficiency of the anaerobic digestion is very low due to various problems such as a pH decrease and an inflow of irregular pollutant loads caused as organic pollutants of the high concentration wastewater are degraded at high rates. Especially, in case of the Korean Peninsula, since the components and degradation degrees of food waste, livestock waste, sewage sludge, etc. containing organic components of high concentration are diversified and the four seasons are clear, the load changes and the temperature load changes may be shown variously. Accordingly, specific reactors and an arrangement of such reactors are required to adapt readily to such circumstances.
A typical method for meeting with the above requirements is an upflow anaerobic sludge blanket (UASB).
However, the UASB has shown limitations in the efficiency due to some problems in a mixing process, a supply of microorganisms, an increase in size of an apparatus, an approach to a plug flow reactor (PFR), an approach to a rapid oxidation, and the like.
The most significant problem of existing anaerobic treatments is the wastewater treatment after the anaerobic treatment. Since the wastewater contains high concentration organic pollutants and ammonia, it is very difficult to appropriately treat the wastewater using the existing aerobic treatment method. That is, since the concentration of organic pollutants is very high and the organic pollutants are non-degradable, the treatment period is usually long and an ammonia stripping process by increasing pH is required, thus resulting in high cost in the post-treatment.